CVE-2026-102761

critical · 9.3

NetX Duo's WebSocket client resets the unmasking cursor to the first `NX_PACKET` each time it advances through a chained packet, while the loop's upper bound belongs to the current packet. With the standard contiguous packet-pool layout, a masked server frame split across two packets therefore drives the XOR loop through the first packet's unused payload area and on through the second packet's `NX_PACKET` control block. The four-byte WebSocket masking key controls the bytes written, so the corruption is attacker-chosen rather than incidental.

9.3

CVSS

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EPSS (exploit prob.)

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EPSS percentile

2026-09-29

Published

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Weaknesses

CWE-787

References

https://github.com/eclipse-threadx/netxduo/security/advisories/GHSA-6xgx-v7gw-qjph

Query this programmatically:

curl https://evil-db.io/api/v1/cve/CVE-2026-102761